JS1313: Structural Substantiation of Sikorsky S-61N Helicopter Equipped for 11,000 Pound Class B External Load, 1988-08-17, Box: 13, Folder: 15. Shannon Engineering, Inc., records, 8746. Division of Rare and Manuscript Collections. https://aspace3-test.library.cornell.edu/repositories/2/archival_objects/766842 Accessed June 16, 2026.